Keywords: Visco-elastic property; polymer flooding; oil recovery Abstract. Polymer flooding and ASP flooding has improved oil recovery a lot in Daqing oil field. In ASP flooding, the existence of alkali decreases the visco-elastic characteristic of polymer, which decreases the oil recovery of polymer flooding. The aim of this paper was to study the visco-elastic characteristic, shear resistance in high concentration and high molecular weight polymer flooding, and analyzed the suitable parameter of it .They can provide the theory of polymer flooding development and application research.

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Gemini surfactants are chemical compounds known as new generation of surfactants that their molecules has two hydrophilic groups ,two hydrophobic groups and a spacer.They have low CMC value and high surface activity.Gemini surfactants are inapproachable by any surfactants that are used for TOR nowadays.This essay is meant to solve the problems faced in the territory by using the remarkably high surface activity,introducing Gemini surfactants to TOR and launch series of experiments.Meanwhile,it provides technical and theoretical support for applying Gemini surfactants into the field.

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Heavy metals can accumulate in nearby farmland soil through leakage of tailings and suspended dust, thereby posing a threat to local agriculture and human health. This study measured the heavy metal content (mercury, Hg; copper, Cu; zinc, Zn; lead, Pb; cadmium, Cd; selenium, Se; manganese, Mn) of farmland soils and wheat from twelve villages near a tailing dam in Baotou, China to evaluate the potential risks to the local ecosystem and human health. The results of the Contamination Factor (C f ) and Geo-accumulation Index (I geo ) indicated serious soil Hg, Se, and Cu contamination. Nemerow Composite Index (NCI) values showed that ±75% of the total sampling sites suffered heavy metal pollution. Soil Potential Ecological Risk Index (IRs) to the west of the tailings exceeded those to the southwest, demonstrating higher levels of Hg and Cd. The Hazard Quotient (HQ) of Mn for adults and children exceeded 3.0, whereas the HQ of Cu for children exceeded 1.0; the Hazard Index (HIs) for both adults and children exceeded 2.0. The results indicate that long-term consumption of wheat grains contaminated with heavy metals in the study area may result in adverse non-carcinogenic health risks, in particular among children. The accumulation of Cd posed carcinogenic risks to human health in two villages (>1 × 10 −4 ). There is an urgent need to regulate the pollution of farmland soil near the tailings dams to mitigate risks to human health.